Gitelman syndrome (GS) is an inherited renal tubular disorder characterized by hypokalemic alkalosis and hypomagnesemia, due to biallelic pathogenic variants in the solute carrier family 12 member 3 (SLC12A3) gene encoding a sodium-chloride (Na-Cl) cotransporter (NCC). The gene discussed is SLC23A1; the disease is familial primary hypomagnesemia.